My question to you all is, do you think there could be someting a miss here. Surely the degredation on the line over the last 400 metres can't be that bad, after all (and I know ADSLMax is far more forgiving than FTTC would be) I do get an exceptional rate via ADSLMax and I know they are different products/technologies but...
What do you think?
From other users' stats, I have seen 18.5Mb sync speed over 1.3 miles (2100metres) & also 18Mb over 1 mile (1600 metres).
VDSL2 (FTTC) uses higher frequencies than ADSL connections to currently achieve up to 80Mb sync speeds from BT's 17a profile.
On longer lines, attenuation is simply to high to achieve anything (or very little) from the higher frequencies.
However (the good news), all VDSL2 connections start bit loading at the lower frequencies, delivering whatever is physically possible to the end user.
These lower frequencies are the same frequencies as used for ADSL connections.
As VDSL2 "basically" uses the same technology as ADSL, you should at least achieve the same speeds as ADSL over a shorter cable length (assuming the cabinet is not sat immediately outside the exchange).
As ADSL cuts off its bit loading at a lower frequency than VDSL2 does, in theory (& subject to attenuation that increases with frequency), you could/should expect a speed increase.
Additionally, VDSL2 17a connections use up to 3 frequency bands (on shorter good condition copper connections from the cabinet), so a "too high" attenuation at the higher frequency band will not negatively affect anything being delivered via the lower frequency bands.
Bits are generally spread out across the 3 frequency bands for those connections.
Wherever a connection cannot make use of say the highest frequency band, as many bits as possible are "shoved" to the lower frequency band & loaded there instead.
e.g. When my own connection (between 800m & 1100m) is "performing", I can achieve a sync speed of up to 35Mb.
As my attenuation is quite high, I can only use the first 2 frequency bands. Almost all bits are loaded in the lowest band & a few get loaded in the 2nd band.
When my connection is regularly misbehaving (engineer's visit arranged for Saturday), my sync speed is quite often around, or below 20Mb & only the first frequency band is useable.
My sync speed has on occasions been as low as 8Mb.
So, assuming the engineer re-used the same copper pair from the cabinet, only 2.7Mb sync speed definitely indicates a repairable problem.
If he had some difficulty in making the connection to the fibre element, it is possible that DLM in the cabinet saw many connections/disconnections within a very short period of time & took "very aggressive" corrective action by reducing sync speed in an effort to provide a stable connection.
The only other explanation (in my mind) is that the engineer may just have unwittingly "disturbed" a joint that was previously hanging on by the skin of its teeth.
Are you really 1.6 miles (2575 metres) from the cabinet, or is it being incorrectly reported due to what may hopefully be just temporarily too high an attenuation level, due to maybe a "dodgy" disturbed joint?
Good luck in getting this resolved & don't give up all hope just yet.